Abu Dawud
Medicine
Book Number: 022 / Hadith Number: 3883
Narated By AbudDarda' : I heard the Apostle of Allah (pbuh) say: If any of you is suffering from anything or his brother is suffering, he should say: Our Lord is Allah Who is in the heaven, holy is Thy name, Thy command reigns supreme in the heaven and the earth, as Thy mercy in the heaven, make Thy mercy in the earth; forgive us our sins, and our errors; Thou art the Lord of good men; send down mercy from Thy mercy, and remedy, and remedy from Thy remedy on this pain so that it is healed up.